Horizontal directional drilling (HDD) can feel like a bit of a mystery if you’ve never seen it up close. How on earth do we get a metal bit as thick as your arm to go where we want it to, underground?!
It’s a good question, and it’s one of many we hear over and over again.
Customers often ask us the same questions about what’s possible, what’s not, and what to expect with horizontal drilling. We’ve pulled together some of the most common horizontal drilling FAQs we hear on the job to give you a clear picture of how this process works.
What is Horizontal Directional Drilling (HDD)?
Horizontal directional drilling is a method of installing underground utilities such as water, sewer, gas, electric, or communication lines.
Instead of digging long open trenches and setting utilities down in them, HDD uses a drilling rig to bore a path underground, guided by transmitters and locators. This allows new pipes or conduits to be pulled through with minimal surface disruption, making it an efficient alternative to traditional excavation. It’s great for going underneath roads, driveways, or other utilities.
Capabilities Questions
How do you steer the drill head?
The drill head has a slanted-face bit. Operators can stop rotation and push forward in a set direction, using the slant to steer up, down, or sideways. Once the bit is spinning again, it advances straight.
So, drilling does NOT have to be only straight in one direction!
How do you know where the drill head is during drilling?
The transmitter inside the drilling head relays data to a surface locator and the operator’s console. It shows depth, pitch, roll, temperature, and signal strength. GPS isn’t used, but the radio signal is precise enough to keep the bore exactly where it needs to be.
How accurate is horizontal drilling?
HDD is very accurate. With the locator and transmitter system, we can track depth and position within inches. That precision is what allows us to safely cross under roads, rivers, and existing utilities.
Is there a camera on the drill head so you can see underground?
No, there’s no camera down there. Instead, we use a transmitter inside the drill head that sends information about depth, angle, roll, and position up to a locator above ground and to the operator’s screen.
What is the largest pipe diameter you can drill?
With our current equipment, we can drill up to 16 inches in diameter. In rare cases we’ve gone larger, but 16 inches is a reliable benchmark for most projects.
How far can you drill in one run?
Our longest continuous run so far was 1,760 feet of 12-inch pipe in Jim Thorpe, PA. That entire project was drilled through solid rock!
While most jobs are shorter, it shows just how far our rigs can go when the project calls for it.
Costs and Efficiency
How much does horizontal drilling cost?
Every project is different, so there’s no one-size-fits-all price. Soil type, pipe size, distance, jobsite setup, permitting, and labor rules all affect the final number. As an example, we have done large-scale commercial projects in the six figures. Smaller residential projects come in at much lower figures and are competitive with trench digging if it involves any concrete replacement or fixes to surface systems after the project.
Is boring cost-effective for small projects, like under a driveway?
Absolutely. Even for short shots, HDD often saves money and headaches by avoiding the damage and long-term “scars” caused by trenching. A bored line under a driveway means no sinking asphalt patch and no bare strip in the lawn.
How long does a typical horizontal drilling project take?
Residential projects may be done in a few hours, while longer commercial runs can take several days or more. Ground conditions and setup play a big role in timelines.
Ground Conditions
Can you drill through rock?
Yes. Solid formations like limestone, sandstone, and shale can all be drilled with the right equipment.
Loose rock and cobbles are actually more difficult, and sometimes those conditions make HDD impractical.
Can you drill under streams or rivers?
Yes, but these projects require extra permitting and environmental safeguards.
Stream crossings are heavily regulated, and planning must address soil conditions, water flow, and habitat protection.
What equipment do you use for different job sizes?
We own both smaller rigs for residential driveways and service lines, and larger rigs capable of major utility or municipal projects.
Matching the right drill to the job keeps costs reasonable and timelines efficient.
Jobsite Considerations
Does the drill line have to be straight?
Not at all. HDD rigs are designed to steer underground. That said, they can’t make sharp corners. Most of our rigs allow a bend radius between 108 and 145 feet.
Can you drill under or around other utilities?
Yes. We deal with this every day. Before we start, we follow Pennsylvania’s One Call law to mark utilities, then use vac trucks to expose lines and confirm depth. High-pressure gas lines require extra coordination with the utility company.
What happens if you hit an unmarked utility?
Despite Pennsylvania’s One Call system, unmarked private utilities are common. If we encounter one, our crews are trained to stop immediately, assess the situation, and repair or coordinate with the owner as needed. Safety is always the top priority.
Do I need a permit to drill under a road?
Yes. State highways require PennDOT permits, township roads require township approval, and stream crossings can involve extra environmental permits. The complexity varies depending on location.
Environmental Impact
Where does all the dirt go?
Smaller bores usually just compact the soil in place. On larger runs, the drill head creates a slurry of soil and drilling fluid. That mixture is vacuumed out and hauled away for disposal.
Is horizontal drilling environmentally friendly?
Compared to open trenching, HDD is much less disruptive. It protects landscaping, avoids tearing up roads, and reduces traffic detours.
Applications
What kinds of projects use horizontal drilling?
We use HDD to install water, sewer, gas, electric, and communication lines under driveways, roads, parking lots, and streams. If you want the surface left intact, boring is usually the best option.
Can horizontal drilling be used in residential backyards?
Yes. Homeowners often hire us to bore under sidewalks, gardens, patios, or small driveways to run new water, gas, or electric lines without tearing up landscaping.
What’s the difference between horizontal boring and trenching?
Trenching means cutting open the ground surface, while HDD works underground with minimal disruption. Boring avoids patchwork asphalt, uneven lawns, and long restoration times.
Considering Boring For your Next Project? Give Us a Call For a Free Quote!
Horizontal drilling answers a lot of headaches before they even start, saving time, money, and mess. If you’re curious about whether boring is right for your project, or are looking for a horizontal drilling company in Central Pennsylvania, get in touch and we’ll be glad to talk it through.
